ALPHA
ALPHA Surface/Vault version
Product Overview
The standard product of the ALPHA family is a low-noise, three component seismometer designed to be deployed in vaults or shallow surface installations. Its flat amplitude response covers five orders of magnitude in frequency, from 2.7 mHz (360 sec) to 270 Hz with additional options for a long period cut-off at 60 sec or 120 sec. Its intrinsic noise level lies below the New Low Noise Model (NLNM) from 200 sec to approximately 20 Hz. To achieve such a low noise performance the instrument's mechanical section and the feedback electronics each have their own isolated and hermetically sealed enclosures.
The seismometer can be operated within a tilt range of ± 5.0 degrees. Its sensors' mass controls (unlock/lock/centre) are microprocessor driven and can be fully operated remotely. The instrument is shielded against external magnetic disturbances by a Mu-metal sheet inside its casing.
ALPHA Surface/Vault version
Key Features
Instrument Design
- Triaxial topology with three symmetrically orthogonal mounted sensors
- Fine pitched adjustable feet manufactured from phosphor bronze.
- Shielded against external magnetic disturbances by mu-metal inside the casing
- Doubled nested feed back loop.
Instrument Characteristics
- Ultra-Broadband flat frequency response from 2.7 mHz (360 sec) to 270 Hz. Options for low frequency cut-offs at 60 sec and 120 sec available
- Offered in a whole range of sensitivities from 2*750 to 2*10,000 V/m/s (differential output)
- Operational range within ± 5.0 degrees of tilt.
- Cross axis rejection > -75dB.
- Nine independent analogue output channels: x, y, z = Z, N/S, E/W, u, v, w (Galperin) and mass positions for each sensor
- Mass positions can be used to determine ground tilt
Enclosure
- Rugged housing made from 316 stainless steel material.
- Weight 14.5 kg.
- Dimensions: outer diameter 16.5 cm, height 28.4 cm
- Waterproof as per IP68 standard.
Power and Electronics
- Power consumption < 1 Watt within the operating range from 9 to 36 V.
- Input power is protected against reversed polarity.
- The whole electronic circuitry is two stage galvanically isolated.
To obtain a detailed data sheet for this seismometer, please contact GaiaCode Headquarters
Disclaimer: The product specifications and the stated data are subject to change without prior notice.
